This invention relates to trailer hitches for attaching piggyback containers and trailers onto flat cars for over-the-rail transport, and to other applications such as barges where container trailer hitches are utilized.
In the past hitches for maintaining piggyback containers and trailers in place on railway flat cars have utilized a pair of jaws which hold the king pin of the trailer in place on the car. A yoke engages the jaws to maintain the jaws in closed position in transit. A heavy spring biases the yoke into the closed position. To remove the king pin from the jaws, the yoke is moved forward to allow the jaws to open under the action of a tractor or overhead crane.
Previously in order to move the yoke to the open position it was necessary for the operator to insert a bar into the hitch and apply a lever action to force the yoke forward. While maintaining the lever action on the yoke in the open position, the operator was required to manually actuate a stop to hold the yoke in the open position. This was a difficult operation for the operator and at times could be dangerous. This operation required the operator to be on the car to carry out these steps.
In U.S. Pat. No. 3,632,145 a block is movable by force of an operating bar until a spring biased trigger moves vertically to engage the front surface of the block. However to hold the block in open position, the jaws must be manually opened in this patent, necessitating the operator climbing on the car to open the jaws which is considered by some to be a safety hazard.
A one-way gate assembly for a railway trailer hitch includes a pair of movable jaws adapted to assume a first position engaging and holding in place the kingpin of a piggyback trailer. A stiff yoke spring biases a yoke into a first position engaging the jaws to maintain said jaws in the first position. A one-way gate located on the exit side of the jaws is pivotably mounted about a horizontal axis. In one position the gate extends vertically upwardly, blocking exit of a trailer kingpin. A gate spring biases the gate to pivot the gate outwardly and away from said jaws. A first stop engages the base of the gate maintaining the gate in the vertically extending position. The stop is movable longitudinally of said hitch away from the gate to allow the gate to pivot to open position.